Method and system for providing a failover circuit for rerouting logical circuit data in a data network

ABSTRACT

A method and system are provided for providing a failover circuit for rerouting logical circuit data in a data network. An alternate communication path is identified for routing data for a logical circuit in the data network. An inactive logical circuit is then selected in the data network for communicating the data over the alternate communication path. The inactive logical circuit is then designated as a failover circuit for rerouting the data for the logical circuit in the data network. The inactive logical circuit may be selected by selecting a currently unused logical connection in the data network for communicating the data. The inactive logical circuit may also be selected by provisioning an inactive logical circuit in the data network. The inactive logical circuit may be provisioned by sending configuration data describing a logical data path over the alternate communication path to a network device in the data network.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent is related to U.S. patent application Ser. No. 10/348,077,entitled “Method and System for Obtaining Logical Performance Data for aCircuit in a Data Network,” filed on Jan. 21, 2003, and U.S. patentapplication Ser. No. 10/348,592, entitled “Method and System forProvisioning and Maintaining a Circuit in a Data Network,” filed on Jan.21, 2003. This patent is also related to and filed concurrently withU.S. patent application Ser. No. 10/744,281, entitled “Method And SystemFor Utilizing A Logical Failover Circuit For Rerouting Data Between DataNetworks,” filed on Dec. 23, 2003, U.S. patent application Ser. No.10/745,047, entitled “Method And System For Automatically RenamingLogical Circuit Identifiers For Rerouted Logical Circuits In A DataNetwork,” filed on Dec. 23, 2003, U.S. patent application Ser. No.10/745,170, entitled “Method And System For Automatically Identifying ALogical Circuit Failure In A Data Network,” filed on Dec. 23, 2003, U.S.patent application Ser. No. 10/744,921, entitled “Method And System ForAutomatically Rerouting Logical Circuit Data In A Data Network,” filedon Dec. 23, 2003, U.S. patent application Ser. No. 10/745,168, entitled“Method And System For Automatically Rerouting Logical Circuit Data In AVirtual Private Network,” filed on Dec. 23, 2003, U.S. patentapplication Ser. No. 10/745,116, entitled “Method And System ForAutomatically Rerouting Data From An Overbalanced Logical Circuit In AData Network,” filed on Dec. 23, 2003, U.S. patent application Ser. No.10/744,283, entitled “Method And System For Real Time SimultaneousMonitoring Of Logical Circuits In A Data Network,” filed on Dec. 23,2003, U.S. patent application Ser. No. 10/744,555, entitled “Method AndSystem For Prioritized Rerouting Of Logical Circuit Data In A DataNetwork,” filed on Dec. 23, 2003. All of the above-referencedapplications are assigned to the same assignee this patent and areexpressly incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to rerouting data in a data network. Moreparticularly, the present invention is related to providing a failovercircuit for rerouting logical circuit data in a data network.

BACKGROUND OF THE INVENTION

Data networks contain various network devices, such as switches, forsending and receiving data between two locations. For example, framerelay and Asynchronous Transfer Mode (“ATM”) networks containinterconnected network devices that allow data packets or cells to bechanneled over a circuit through the network from a host device to aremote device. For a given network circuit, the data from a hostlocation is delivered to the network through a physical circuit such asa T1 line that links to a switch of the network. The remote device thatcommunicates with the host through the network also has a physicalcircuit to a switch of the network. The communication path between theswitches associated with the host and the remote device that passesthrough the network is a logical circuit.

In frame relay and ATM networks, end devices do not select differentroutes for data packets or cells sent between the host and the remotelocation, but always send the data packets or cells through the samepath. A host device may have many logical circuits, such as permanentvirtual circuits (“PVCs”) or switched virtual circuits (“SVCs”), linkedto many remote locations. For example, a PVC sends and receives datapackets or cells through the same path leading to the switch of theremote device's physical connection.

In large-scale networks, the host and remote end devices of a networkcircuit may be connected across different local access and transportareas (“LATAs”) which may in turn be connected to one or moreInter-Exchange Carriers (“IEC”) for transporting data between the LATAs.These connections are made through physical trunk circuits utilizingfixed logical connections known as Network-to-Network Interfaces(“NNIs”).

Periodically, failures may occur to the trunk circuits or the NNIs ofnetwork circuits in large-scale networks causing lost data. Currently,such network circuit failures are handled by dispatching technicians oneach end of the network circuit (i.e., in each LATA) in response to areported failure. The technicians manually access a logical elementmodule to troubleshoot the logical circuit portion of the networkcircuit. The logical element module communicates with the switches inthe data network and provides the technician with the status of thelogical circuit. If the technician determines the logical circuit isoperating properly, the technician then accesses a physical elementmodule to troubleshoot the physical circuit portion of the networkcircuit to determine the cause of the failure and then repair it. Thesecurrent methods, however, suffer from several drawbacks. One drawback isthat troubleshooting the logical and physical circuits is time consumingand results in dropped data packets or cells until the failure isrepaired. Furthermore, in most instances, troubleshooting the physicalcircuit requires taking the network circuit out of service to performtesting, thus increasing the downtime and loss of data in the networkcircuit. Moreover, if the failure cannot be isolated by the techniciansin a LATA, or the failure is located at the interface to the IEC,cooperative testing with the IEC must also be coordinated to isolate thefailure leading to a further increase in downtime and loss of data inthe network circuit.

It is with respect to these considerations and others that the presentinvention has been made.

SUMMARY OF THE INVENTION

In accordance with the present invention, the above and other problemsare solved by methods for providing a failover circuit for reroutinglogical circuit data in a data network. According to one method, analternate communication path is identified for routing data for alogical circuit in the data network. An inactive logical circuit is thenselected in the data network for communicating the data over thealternate communication path. The inactive logical circuit is thendesignated as a failover circuit for rerouting the data for the logicalcircuit in the data network.

The alternate communication path may be identified by identifying alogical identifier for the logical circuit. Based on the logicalidentifier, a first end and a second end of the logical circuit in thedata network are determined. Finally, an alternate communication pathincluding the first end and the second end of the logical circuit isidentified in the data network. The inactive logical circuit may beselected by selecting a currently unused logical connection in the datanetwork for communicating the data. The inactive logical circuit mayalso be selected by provisioning an inactive logical circuit in the datanetwork. The inactive logical circuit may be provisioned by sendingconfiguration data describing a logical data path over the alternatecommunication path to a network device in the data network.

The data network may be a frame relay network or an asynchronoustransfer mode (“ATM”) network. The logical circuit may be a permanentvirtual circuit (“PVC”) or a switched virtual circuit (“SVC”). Thelogical identifier may be a data link connection identifier (“DLCI”) ora virtual path/virtual circuit identifier (“VPI/VCI”). Each logicalconnection may include a network-to-network interface.

In accordance with other aspects, the present invention relates to asystem for providing a failover circuit for rerouting logical circuitdata in a data network. The system includes a network device forestablishing a communication path for logical circuits in the datanetwork and a logical element module in communication with the networkdevice for configuring logical circuits in the data network. The systemfurther includes a network management module in communication with thelogical element module. The network management module is operative toidentify an alternate communication path for routing data for the alogical circuit in the data network, select an inactive logical circuitin the data network for communicating the data over the alternatecommunication path, and designate the inactive logical circuit as afailover circuit for rerouting the data for the logical circuit in thedata network.

The network management module, in identifying an alternate communicationpath for routing data for a logical circuit in the data network, isoperative to access a network database to identify a logical identifierfor the logical circuit, based on the logical identifier, determine afirst end and a second end of the logical circuit in the data network,and identify an alternate communication path including the first end andthe second end of the logical circuit. The network management module, inselecting an inactive logical circuit in the data network forcommunicating the data over the alternate communication path, isoperative to transmit a request to the logical element module toprovision the inactive logical circuit. The logical element module, inprovisioning the inactive logical circuit, is operative to send datadescribing a logical data path over the alternate communication path tothe network device to provision the inactive logical circuit.

These and various other features as well as advantages, whichcharacterize the present invention, will be apparent from a reading ofthe following detailed description and a review of the associateddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a data network according to an embodiment of theinvention.

FIG. 2 illustrates a local access and transport area (“LATA”) in thedata network of FIG. 1, according to an embodiment of the invention.

FIG. 3 illustrates a network management system which may be utilized toprovide a failover circuit for rerouting logical circuit data in a datanetwork, according to an embodiment of the invention.

FIG. 4 illustrates a failover data network for rerouting logical circuitdata over a logical failover circuit, according to an embodiment of theinvention.

FIG. 5 illustrates a flowchart describing logical operations forproviding a failover circuit for rerouting logical circuit data in adata network, according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention provide for a method and system forproviding a failover circuit for rerouting logical circuit data in adata network. In the following detailed description, references are madeto the accompanying drawings that form a part hereof, and in which areshown by way of illustration specific embodiments or examples. Referringnow to the drawings, in which like numerals represent like elementsthrough the several figures, aspects of the present invention and theexemplary operating environment will be described.

Embodiments of the present invention may be generally employed in a datanetwork 2 as shown in FIG. 1. The data network 2 includes local accessand transport areas (“LATAs”) 5 and 15 which are connected by anInter-Exchange Carrier (“IEC”) 10. It should be understood that theLATAs 5 and 15 may be data networks operated by a commonly owned LocalExchange Carrier (“LEC”). It should be further understood that the IEC10 may include one or more data networks which may be operated by acommonly owned IEC. It will be appreciated by those skilled in the artthat the data network 2 may be a frame relay network, asynchronoustransfer mode (“ATM”) network, or any other network capable ofcommunicating data conforming to Layers 2-4 of the Open SystemsInterconnection (“OSI”) model developed by the International StandardsOrganization, incorporated herein by reference. It will be appreciatedthat these networks may include, but are not limited to, communicationsprotocols conforming to the Multiprotocol Label Switching Standard(“MPLS”) networks and the Transmission Control Protocol/InternetProtocol (“TCP/IP”), which are known to those skilled in the art.

The data network 2 includes a network circuit which channels databetween a host device 112 and a remote device 114 through the LATA 5,the IEC 10, and the LATA 15. It will be appreciated by those skilled inthe art that the host and remote devices 112 and 114 may be local areanetwork (“LAN”) routers, LAN bridges, hosts, front end processors, FrameRelay Access Devices (“FRADs”), or any other device with a frame relay,ATM, or network interface. It will be further appreciated that in thedata network 2, the LATAs 5 and 15 and the IEC 10 may include networkelements (not shown) which support interworking to enable communicationsbetween host and remote devices supporting dissimilar protocols. Networkelements in a data network supporting interworking may translate framerelay data packets or frames sent from a host FRAD to ATM data packetsor cells so that a host device may communicate with a remote devicehaving an ATM interface. The LATAs 5 and 15 and the IEC 10 may furtherinclude one or more interconnected network elements, such as switches(not shown), for transmitting data. An illustrative LATA data networkwill be discussed in greater detail in the description of FIG. 2 below.

The network circuit between the host device 112 and the remote device114 in the data network 2 includes a physical circuit and a logicalcircuit. As used in the foregoing description and the appended claims, aphysical circuit is defined as the physical path that connects the endpoint of a network circuit to a network device. For example, thephysical circuit of the network circuit between the host device 112 andthe remote device 114 includes the physical connection 121 between thehost device 112 and the LATA 5, the physical connection 106 between theLATA 5 and the IEC 10, the physical connection 108 between the IEC 10and the LATA 15, and the physical connection 123 between the LATA 15 andthe remote device 114. Routers and switches within the LATAs 5 and 15and the IEC 10 carry the physical signal between the host and remote enddevices 112 and 114 through the physical circuit.

It should be understood that the host and remote devices may beconnected to the physical circuit described above using user-to-networkinterfaces (“UNIs”). As is known to those skilled in the art, an UNI isthe physical demarcation point between a user device (e.g, a hostdevice) and a public data network. It will further be understood bythose skilled in the art that the physical connections 106 and 108 mayinclude trunk circuits for carrying the data between the LATAs 5 and 15and the IEC 10. It will be further understood by those skilled in theart that the connections 121 and 123 may be any of various physicalcommunications media for communicating data such as a 56 Kbps line or aT1 line carried over a four-wire shielded cable or over a fiber opticcable.

As used in the foregoing description and the appended claims, a logicalcircuit is defined as a portion of the network circuit wherein data issent over variable communication data paths or logical connectionsestablished between the first and last network devices within a LATA orIEC network and over fixed communication data paths or logicalconnections between LATAs (or between IECs). Thus, no matter what paththe data takes within each LATA or IEC, the beginning and end of eachlogical connection between networks will not change. For example, thelogical circuit of the network circuit in the data network 2 may includea variable communication path within the LATA 5 and a fixedcommunication path (i.e., the logical connection 102) between the LATA 5and the IEC 10. It will be understood by those skilled in the art thatthe logical connections 102 and 104 in the data network 2 may includenetwork-to-network interfaces (“NNIs”) between the last sending switchin a LATA and the first receiving switch in an IEC.

As is known to those skilled in the art, each logical circuit in a datanetwork may be identified by a unique logical identifier. In frame relaynetworks, the logical identifier is called a Data Link ConnectionIdentifier (“DLCI”) while in ATM networks the logical identifier iscalled a Virtual Path Identifier/Virtual Circuit Identifier (“VPI/VCI”).In frame relay networks, the DLCI is a 10-bit address field contained inthe header of each data frame and contains identifying information forthe logical circuit as well as information relating to the destinationof the data in the frame and service parameters for handling networkcongestion. For example, in the data network 2 implemented as a framerelay network, the designation DLCI 100 may be used to identify thelogical circuit between the host device 112 and the remote device 114.It will be appreciated that in data networks in which logical circuitdata is communicated through more than one carrier (e.g., an LEC and anIEC) the DLCI designation for the logical circuit may change in aspecific carrier's network. For example, in the data network 2, thedesignation DLCI 100 may identify the logical circuit in the LATA 5 andLATA 15 but the designation DLCI 800 may identify the logical circuit inthe IEC 10.

Illustrative service parameters which may be included in the DLCIinclude a Committed Information Rate (“CIR”) parameter and a CommittedBurst Size (“Bc”) parameter. As is known to those skilled in the art,the CIR represents the average capacity of the logical circuit and theBc represents the maximum amount of data that may be transmitted. Itwill be appreciated that the logical circuit may be provisioned suchthat when the CIR or the Bc is exceeded, the receiving switch in thedata network will discard the frame. It should be understood that thelogical circuit parameters are not limited to CIR and Bc and that otherparameters known to those skilled in the art may also be provisioned,including, but not limited to, Burst Excess Size (“Be”) and CommittedRate Measurement Interval (“Tc”). In ATM networks, the VPI/VCI is anaddress field contained in the header of each ATM data cell and containsidentifying information for the logical circuit as well as informationspecifying a data cell's destination and specific bits which mayindicate, for example, the existence of congestion in the network and athreshold for discarding cells.

It should be understood that the logical circuit in the data network 2may be a permanent virtual circuit (“PVC”) available to the network atall times or a temporary or a switched virtual circuit (“SVC”) availableto the network only as long as data is being transmitted. It should beunderstood that the data network 2 may further include additionalswitches or other interconnected network elements (not shown) creatingmultiple paths within each LATA and IEC for defining each PVC or SVC inthe data network. It will be appreciated that the data communicated overthe logical connections 102 and 104 may be physically carried by thephysical connections 106 and 108.

The data network 2 may also include a failover network 17 for reroutinglogical circuit data, according to an embodiment of the invention. Thefailover network 17 may include a network failover circuit includingphysical connections 134 and 144 and logical connections 122 and 132 forrerouting logical circuit data in the event of a failure in the networkcircuit between the host device 112 and the remote device 114. Thefailover network 17 will be described in greater detail in thedescription of FIG. 4 below. The data network 2 may also include anetwork management system 175 in communication with the LATA 5, the LATA15, and the failover network 17. The network management system 175 maybe utilized to obtain status information for the logical and physicalcircuit between the host device 112 and the remote device 114. Thenetwork management system 175 may also be utilized to provision failovercircuits for rerouting logical data in the data network 2 between thehost device 112 and the remote device 114. The network management system175 will be discussed in greater detail in the description of FIG. 3below.

FIG. 2 illustrates the LATA 5 in the data network 2 described in FIG. 1above, according to an embodiment of the present invention. As shown inFIG. 2, the LATA 5 includes interconnected network devices such asswitches 186, 187, and 188. It will be appreciated that the data network2 may also contain other interconnected network devices and elements(not shown) such as digital access and cross connect switches (“DACS”),channel service units (“CSUs”), and data service units (“DSUs”). Itshould be understood that the switches 186, 187, and 188 establish thecommunication or connection data paths for logical circuits in a datanetwork. As discussed above in the description of FIG. 1, the connectiondata paths of a logical circuit within a data network may vary betweenthe first and last network devices in a data network. For example, asshown in FIG. 2, the logical circuit in the LATA 5 may include thecommunication path 185 between the switches 186 and 188 or thecommunication path 184 between the switches 186, 187, and 188. Asdiscussed above, it should be understood that the actual path taken bydata through the LATA 5 is not fixed and may vary from time to time,such as when automatic rerouting takes place.

It will be appreciated that the switches 186, 187, and 188 may include asignaling mechanism for monitoring and signaling the status of thelogical circuit in the data network 2. Each time a change in the statusof the logical circuit is detected (e.g., a receiving switch beginsdropping frames), the switch generates an alarm or “trap” which may thenbe communicated to a management station, such as a logical elementmodule (described in detail in the description of FIG. 3 below), in thenetwork management system 175. In one embodiment, the signalingmechanism may be in accord with a Local Management Interface (“LMI”)specification, which provides for the sending and receiving of “statusinquiries” between a data network and a host or remote device. The LMIspecification includes obtaining status information through the use ofspecial management frames (in frame relay networks) or cells (in ATMnetworks). In frame relay networks, for example, the special managementframes monitor the status of logical connections and provide informationregarding the health of the network. In the data network 2, the host andremote devices 112 and 114 receive status information from theindividual LATAs they are connected to in response to a status requestsent in a special management frame or cell. The LMI status informationmay include, for example, whether or not the logical circuit iscongested or whether or not the logical circuit has failed. It should beunderstood that the parameters and the signaling mechanism discussedabove are optional and that other parameters and mechanisms may also beutilized to obtain connection status information for a logical circuit.

FIG. 3 illustrates the network management system 175 which may beutilized to provision failover circuits for rerouting logical circuitdata from a failed logical circuit in the data network 2 of FIG. 1,according to an embodiment of the invention. The network managementsystem 175 includes a service order system 160, a network database 170,a logical element module 153, a physical element module 155, a networkmanagement module 176, and a test module 180. The service order system160 is utilized in the data network 2 for receiving service orders forprovisioning network circuits. The service order includes informationdefining the transmission characteristics (i.e., the logical circuit) ofthe network circuit. The service order also contains the access speed,CIR, burst rates, and excess burst rates. The service order system 160communicates the service order information to a network database 170over management trunk 172. The network database 170 assigns and storesthe parameters for the physical circuit for the network circuit such asa port number on the switch 186 for transmitting data over the physicalconnection 121 to and from the host device 112.

The network database 170 may also be in communication with an operationssupport system (not shown) for assigning physical equipment to thenetwork circuit and for maintaining an inventory of the physicalassignments for the network circuit. An illustrative operations supportsystem is “TIRKS”® (Trunks Integrated Records Keeping System) marketedby TELECORDIA™ TECHNOLOGIES, Inc. of Morristown, N.J. The networkdatabase 170 may also be in communication with a Work ForceAdministration and Control system (“WFA/C”) (not shown) used to assignresources (i.e., technicians) to work on installing the physicalcircuit.

The network management system 175 also includes the logical elementmodule 153 in communication with the switches 186, 187, and 188 throughmanagement trunks 183. The logical element module 153 may be utilized toprovision logical circuits in the data network 2 by programming portscontained in the switches 186, 187, and 188. The logical element module153 runs a network management application program to monitor theoperation of logical circuits which includes receiving trap datagenerated by the switches which indicate the status of logicalconnections. The trap data may be stored in the logical element module153 for later analysis and review. The logical element module 153 isalso in communication with the network database 170 via managementtrunks 172 for accessing information regarding logical circuits such asthe logical identifier data. The logical identifier data may include,for example, the DLCI or VPI/VCI header information for each data frameor cell in the logical circuit including the circuit's destination andservice parameters. The logical element module 153 may consist ofterminals (not shown) that display a map-based graphical user interface(“GUI”) of the logical connections in the data network. An illustrativelogical element module is the NAVISCORE™ system marketed by LUCENTTECHNOLOGIES, Inc. of Murray Hill, N.J.

The network management system 175 further includes the physical elementmodule 155 in communication with the physical connections of the networkcircuit via management trunks (not shown). The physical element module155 runs a network management application program to monitor theoperation and retrieve data regarding the operation of the physicalcircuit. The physical element module 155 is also in communication withthe network database 170 via management trunks 172 for accessinginformation regarding physical circuits, such as line speed. Similar tothe logical element module 153, the physical logical element module 155may also consist of terminals (not shown) that display a map-based GUIof the physical connections in the LATA 5. An illustrative physicalelement module is the Integrated Testing and Analysis System (“INTAS”),marketed by TELECORDIA™ TECHNOLOGIES, Inc. of Morristown, N.J., whichprovides flow-through testing and analysis of telephony services.

The physical element module 155 troubleshoots the physical connectionsfor a physical circuit by communicating with test module 180, whichinterfaces with the physical connections via test access point 156. Thetest module 180 obtains the status of the physical circuit bytransmitting “clean” test signals to test access point 156 (shown inFIG. 2) which “loops back” the signals for detection by the test module180. It should be understood that there may be multiple test accesspoints on each of the physical connections for the physical circuit.

The network management system 175 further includes the networkmanagement module 176 which is in communication with the service ordersystem 160, the network database 170, the logical element module 153,and the physical element module 155 through communications channels 172.It should be understood that in one embodiment, the network managementsystem 175 may also be in communication with the LATA 15, the IEC 10,and the failover network 17. The communications channels 172 may be on alocal area network (“LAN”). The network management module 176 mayconsist of terminals (not shown), which may be part of a general-purposecomputer system that displays a map-based GUI of the logical connectionsin data networks. The network management module 176 may communicate withthe logical element module 153 and the physical element module 155 usinga Common Object Request Broker Architecture (“CORBA”). As is known tothose skilled in the art, CORBA is an open, vendor-independentarchitecture and infrastructure which allows different computerapplications to work together over one or more networks using a basicset of commands and responses. The network management module 176 mayalso serve as an interface for implementing logical operations toprovision and maintain network circuits. The logical operations may beimplemented as machine instructions stored locally or as instructionsretrieved from the logical and physical element modules 153 and 155. Anillustrative network management module is the Broadband NetworkManagement System® (“BBNMS”) marketed by TELECORDIA™ TECHNOLOGIES, Inc.of Morristown, N.J.

FIG. 4 illustrates a failover data network for rerouting logical circuitdata, according to one embodiment of the present invention. As shown inFIG. 4, the failover network 17 includes an IEC 20, a LATA 25, and anIEC 30. The failover network further includes a network failover circuitwhich includes a physical failover circuit and a logical failovercircuit. The physical failover circuit includes the physical connection134 between the LATA 5 (shown in FIG. 1) and the IEC 20, the physicalconnection 136 between the IEC 20 and the LATA 25, the physicalconnection 138 between the LATA 25 and the IEC 30, and the physicalconnection 144 between the IEC 30 and the LATA 15 (shown in FIG. 1).Similarly, the logical failover circuit may include the logicalconnection 122 between the LATA 5 (shown in FIG. 1) and the IEC 20, thelogical connection 124 between the IEC 20 and the LATA 25, the logicalconnection 126 between the LATA 25 and the IEC 30, and the logicalconnection 132 between the IEC 30 and the LATA 15 (shown in FIG. 1). Itshould be understood that in one embodiment, the network failovercircuit illustrated in the failover network 17 may include a dedicatedphysical circuit and a dedicated logical circuit provisioned by anetwork service provider serving the LATAs 5, 15, and 25 and the IECs 20and 30, for rerouting logical data from a failed logical circuit.

FIG. 5 illustrates a flowchart describing logical operations 500 forproviding a failover circuit for rerouting logical circuit data in adata network, according to an embodiment of the invention. The logicaloperations 500 begin at operation 505 where the network managementmodule 176 identifies an alternate communication path for a logicalcircuit in the data network 2. The alternate communication path may bedetermined by identifying a logical connection or NNI in the logicalcircuit. Information related to each logical connection in a logicalcircuit may be stored in the database 170 including the first and secondends of the logical circuit to which the logical connection belongs.Once the ends of a logical circuit are determined by accessing thedatabase 170, the network management module 176 may select an alternatecommunication path including the first and second ends of the logicalcircuit for rerouting data. For example, an the network managementmodule 176 may identify the alternate path between the host device 112and the remote device 114 which includes the logical connections 122,124, 126, and 132 (as shown in FIG. 4) as an alternate communicationpath for the logical circuit shown in FIG. 1 which includes the logicalconnections 102 and 104. The logical operations 500 then continue fromoperation 505 to operation 510.

At operation 510, the network management module 176 selects a logicalfailover circuit in the data network 2 to reroute the logical circuitdata over the previously identified alternate communication path. Itwill be appreciated that in one embodiment, the logical failover circuitmay be selected by provisioning an inactive logical circuit (i.e., thelogical circuit which does not carry any data) as the logical failovercircuit. In this embodiment, the network management module 176 mayprovision the logical failover circuit by communicating configurationdata to the logical element module 153 with instructions to provisionthe logical failover circuit. The logical element module 153 locates theappropriate switches in the data network and programs the appropriateports to provision the logical failover circuit.

For example, in data network 2, the-logical element module 153 wouldaccess and program the ports in the switches 186, 187, and 188 in theLATA 5 to communicate data from the host device 112 to the remote device114 over the logical connection 122. Similarly, the logical elementmodule 153 would access and program the ports in the switches (notshown) in the LATA 25 to deliver data from the LATA 5 over the logicalconnections 124 and 126 (shown in the failover network 17 of FIG. 2). Itwill be appreciated that the in this embodiment, the network managementmodule 176, in conjunction with the logical element module 153, may beconfigured to provision logical circuits automatically. An illustrativemethod detailing the automatic provisioning of logical circuits in adata network is presented in U.S. patent application Ser. No.10/348,592, entitled “Method And System For Provisioning And MaintainingA Circuit In A Data Network,” filed on Jan. 23, 2003, and assigned tothe same assignee as this patent, which is expressly incorporated hereinby reference.

It will be appreciated that in another embodiment, the logical failovercircuit may be selected by utilizing an existing logical circuit whichis normally utilized for communicating data traffic in the data network2 but which is currently inactive. In this embodiment, the selection ofthe logical failover circuit may also include determining whether one ormore logical connections in the logical circuit are currentlycommunicating data traffic or are currently unused. If currently unused,the logical connections may be selected for rerouting logical data. Forexample, a technician at the logical element module 153 or the networkmanagement module 176 may utilize a map-based GUI displaying the logicalconnections in the LATA data networks 5 and 15 and their status. Acurrently unused logical circuit may then be selected as a logicalfailover circuit for communicating logical circuit data from a failedlogical circuit. The logical operations 500 then continue from operation510 to operation 515.

At operation 515, the network management module 176 designates thepreviously selected inactive logical circuit as a logical failovercircuit for rerouting logical circuit data. The logical operations 500then end. It will be appreciated that the network management module 176may be utilized to reroute data to the logical failover circuit afteridentifying a logical circuit failure in the data network 2. Anillustrative method detailing a method for automatically identifying alogical circuit failure in a data network is presented in U.S. patentapplication Ser. No. 10/745,170, entitled “Method And System ForAutomatically Identifying A Logical Circuit Failure In A Data Network,”filed on Dec. 23, 2003, and assigned to the same assignee as thispatent, which is expressly incorporated herein by reference. Once thenetwork management module 176 has identified a logical circuit failureit may initiate an automatic reroute procedure using the failovernetwork 17. An illustrative method detailing rerouting logical circuitdata over a failover network is presented in U.S. patent applicationSer. No. 10/744,921, entitled “Method And System For AutomaticallyRerouting Logical Circuit Data In A Data Network,” filed on Dec. 23,2003, and assigned to the same assignee as this patent, which isexpressly incorporated herein by reference.

It will be appreciated that the embodiments of the present inventionprovide for a method and system for providing a failover circuit forrerouting logical circuit data in a data network. The variousembodiments described above are provided by way of illustration only andshould not be construed to limit the invention. Those skilled in the artwill readily recognize various modifications and changes that may bemade to the present invention without following the example embodimentsand applications illustrated and described herein, and without departingfrom the true spirit and scope of the present invention, which is setforth in the following claims.

1. A method for providing a failover circuit for rerouting logical circuit data in a data network, the method comprising: receiving, via a network management system, status information indicating a network circuit failure in the data network, the status information indicating that a switch in the data network is discarding frames or cells, wherein the network management system is separate from switches of the data network used to communicate data through the data network; in response to the status information, identifying, via the network management system, an alternate communication path for routing the data for a logical circuit in the data network, wherein the logical circuit includes a communication path through first and second local access and transport areas and an inter-exchange carrier between the first and second local access and transport areas; selecting, via the network management system, an inactive logical circuit in the data network for communicating the data over the alternate communication path, wherein selecting the inactive logical circuit in the data network for communicating the data over the alternate communication path comprises selecting a currently unused logical connection in the data network for communicating the data, and wherein selecting the currently unused logical connection comprises selecting the currently unused logical connection through a failover network to reroute the data around the inter-exchange carrier; and designating, via the network management system, the inactive logical circuit as a failover circuit for rerouting the data for the logical circuit in the data network.
 2. The method of claim 1, wherein identifying the alternate communication path for routing data for the logical circuit in the data network comprises: identifying a logical identifier for the logical circuit; based on the logical identifier, determining a first end and a second end of the logical circuit in the data network; and identifying the alternate communication path including the first end and the second end of the logical circuit.
 3. The method of claim 1, wherein selecting the inactive logical circuit in the data network comprises provisioning the inactive logical circuit in the data network.
 4. The method of claim 1, wherein the currently unused logical connection comprises a network-to-network interface.
 5. The method of claim 1, wherein the failover circuit is a permanent virtual circuit.
 6. The method of claim 1, wherein the failover circuit is a switched virtual circuit.
 7. The method of claim 2, wherein the logical identifier is a data link connection identifier (DLCI).
 8. The method of claim 2, wherein the logical identifier is a virtual path/virtual circuit identifier (VPI/VCI).
 9. A system for providing a failover circuit for rerouting logical circuit data in a data network, the system comprising: a logical element module in communication with at least one network device for configuring at least one logical circuit in a data network, wherein the at least one logical circuit includes a communication path through first and second local access and transport areas and an inter-exchange carrier between the first and second local access and transport areas; and a network management module, in communication with the logical element module and separate from switches of the data network used to communicate data through the data network, for: receiving status information indicating a network circuit failure in the data network, the status information indicating that a switch in the data network is discarding frames or cells; in response to the status information, identifying an alternate communication path for routing the data for the at least one logical circuit in the data network; selecting an inactive logical circuit in the data network for communicating the data over the alternate communication path, wherein selecting the inactive logical circuit in the data network for communicating the data over the alternate communication path comprises transmitting a request to the logical element module to provision the inactive logical circuit, and wherein the logical element module is to provision the inactive logical circuit through a failover network to reroute the data around the inter-exchange carrier; and designating the inactive logical circuit as a failover circuit for rerouting the darn for the logical circuit in the data network.
 10. The system of claim 9, wherein the network management module, in identifying the alternate communication path for routing the data for the at least one logical circuit in the data network, is operative to: access a network database to identify a logical identifier for the at least one logical circuit; based on the logical identifier, determine a first end and a second end of the at least one logical circuit in the data network; and identify the alternate communication path including the first end and the second end of the at least one logical circuit.
 11. The system of claim 9, wherein the logical element module, in provisioning the inactive logical circuit, is operative to send data describing a logical data path over the alternate communication path to the at least one network device to provision the inactive logical circuit.
 12. The system of claim 9, wherein the at least one logical circuit comprises at least one logical connection.
 13. The system of claim 12, wherein the at least one logical connection comprises a network-to-network interface.
 14. The system of claim 9, wherein the failover circuit is a permanent virtual circuit.
 15. The system of claim 9, wherein the failover circuit is a switched virtual circuit.
 16. The system of claim 9, wherein the data network is a frame relay logical network.
 17. The system of claim 10, wherein the logical identifier is a data link connection identifier (DLCI).
 18. The system of claim 10, wherein the logical identifier is a virtual path/virtual circuit identifier (VPI/VCI).
 19. A method for providing a failover circuit for rerouting logical circuit data in a data network, the method comprising: receiving, via a network management system, a customer report indicating a network circuit failure in the data network, wherein indicating the network circuit failure comprises receiving trap data indicating the network circuit failure, wherein the trap data comprises status information indicating that a switch in the data network is discarding frames or cells, wherein the network management system is separate from switches of the data network used to communicate data through the data network; in response to the customer report, identifying, via the network management system, an alternate communication path for routing the data for a logical circuit in the data network, wherein the logical circuit includes a communication path through first and second local access and transport areas and an inter-exchange carrier between the first and second local access and transport areas; selecting, via a network management system, an inactive logical circuit in the data network for communicating the data over the alternate communication path, wherein selecting the inactive logical circuit in the data network for communicating the data over the alternate communication path comprises provisioning the inactive logical circuit in the data network, and wherein provisioning the inactive logical circuit comprises provisioning the inactive logical circuit through a failover network to reroute the data around the inter-exchange carrier; and designating, via a network management system, the inactive logical circuit as a failover circuit for rerouting the data for the logical circuit in the data network.
 20. The method of claim 19, wherein identifying the alternate communication path for routing the data for the logical circuit in the data network comprises: identifying a logical identifier for the logical circuit; based on the logical identifier, determining a first end and a second end of the logical circuit in the data network; and identifying the alternate communication path including the first end and the second end of the logical circuit.
 21. The method of claim 19, wherein provisioning the inactive logical circuit in the data network comprises sending configuration data describing a logical data path over the alternate communication path to a network device in the data network.
 22. The method of claim 1, wherein the network management system is configured to monitor a plurality of other logical circuits to detect a failure in any of the plurality of other logical circuits and at least one of select or provision any of a plurality of other failover circuits in the failover network in response to detecting that any of the plurality of other logical circuits has failed.
 23. The method of claim 9, wherein the logical element module is further configured to monitor a plurality of other logical circuits to detect a failure in any of the plurality of other logical circuits, and wherein the network management module is further configured to identify any of a plurality of other failover circuits in the failover network in response to the logical element module detecting that any of the plurality of other logical circuits has failed. 